Wholly aromatic mesomorphic polyester amide imides and the preparation thereof

ABSTRACT

Wholly aromatic mesomorphic polyester amide imides which form a liquid-crystalline fiber-forming melt below 320° C. and are composed of 
     (a) from 5 to 35 mole % of repeat units of the formula I and/or II ##STR1##  where the Xs is the formulae I and II can be identical or different and each is --O--, --S--, --SO 2  --, --CO--, --CH 2  -- or ═C(CH) 3 ) 2  and n is 0 or 1. 
     (b) from 0 to 30 mole % of repeat units of the formulae III and/or IV ##STR2## (c) a molar amount corresponding to the total amount of components a and b of one or more of the repeat units of the formulae V, VI, VII, VIII and IX ##STR3## (d) if desired from 5 to 25 mole % of one or more of the repeat units of the formulae X, XI and XII ##STR4## (e) repeat units of the formula XIII ##STR5## the mole percentages of components (a), (b), (c), (d) and (e) adding up to 100 mole % in each case, 
     the preparation thereof and fibers, films and moldings prepared therefrom.

The present invention relates to wholly aromatic mesomorphic polyesteramide imides which form a liquid-crystalline fiber-forming melt below320° C.

Liquid-crystalline polyester amides and polyester imides are known.However, these polymers are in need of improvement in heat distortionresistance, processability, and, in particular, abrasion resistance. EPApplication No. 81,900 discloses polyester amides which comprise 40% ormore coaxial units such as aromatic dicarboxylic acids,hydroxybenzenecarboxylic acids, bisphenols and aminophenols and containan adequate amount of nonlinear radicals which are derived from aromaticm-amino compounds and 2-nuclear aromatic sulfones, but does not revealthe composition required to obtain the desired combination ofproperties, U.S. Pat. No. 4,176,223 describes polyester imides which arebased on naphthalenedicarboxylic acid, substituted hydroquinones and4-(4'-carboxyphthalimido)benzoic acid. However, these polymers requirefor processing from the melt temperatures of 330° C. or more. The sameis true of the polyester imides known from U.S. Pat. No. 4,383,105,which are based on hydroxynaphthalenecarboxylic acid, terephthalic acid,p-hydroxybenzoic acid and 4-(4'-hydroxyphthalimido)phenol.

It is an object of the present invention to provide wholly aromaticmesomorphic polyester amide imides which form a liquid-crystallinefiber-forming melt below 320° C. and thus are easy to process and, inaddition, have a high heat distortion resistance, a high abrasionresistance and a high resilience.

We have found that this object is achieved with wholly aromaticmesomorphic polyester amide imides which form a liquid-crystallinefiber-forming melt below 320° C. and are composed of

(a) from 5 to 35 mole % of repeat units of the formula I and/or II##STR6## where the Xs in the formulae I and II can be identical ordifferent and each is --O--, --S--, --SO₂ --, --CO--, --CH₂ -- or--(CH₃)₂ and n is 0 or 1,

(b) from 0 to 30 mole % of repeat units of the formulae III and/or IV##STR7## (c) a molar amount corresponding to the total amount ofcomponents a and b of one or more of the repeat units of the formulae V,VI, VII, VIII and IX ##STR8## (d) if desired from 5 to 25 mole % of oneor more of the repeat units of the formulae X, XI and XII ##STR9## (e)repeat units of the formula XIII ##STR10## mole percentages ofcomponents, (a), (b), (c), (d) and (e) adding up to 100 mole % in eachcase.

The novel wholly aromatic polyester amide imides have the advantage ofcombining a high heat distortion resistance with a smoothabrasion-resistant surface. The novel polyester amide imides furtherhave high stiffness, strength and resilience. In addition, they aresubstantially resistant to chemicals and of low flammability and can beprocessed from the melt at below 320° C.

The liquid-crystalline state of the polyester amide imides can bedetected with a polarization microscope by a method described in GermanPublished Application DAS No. 2,520,819. Applied in a thickness of 10 μmbetween glass plates and viewed between crossed polarizers, the polymermelts have textures which can be ascribed to a mesomorphic phase.

The polyester amide imides according to the invention are composed of

(a) from 5 to 35 mole %, in particular from 7 to 25 mole %, of repeatunits of the formulae I and/or II ##STR11## where the Xs in the formulaeI and II can be identical of different and each is --O--, --S--, --SO₂--, --CO--, --CH₂ -- or ═C(CH₃)₂, in particular --O--, --SO₂ -- or --CH₂--, and n is 0 or 1, suitable compounds being for example4,4'-bis[(4-carboxy)-N-phthalimido]diphenyl ether,4,4'-bis[(4-carboxy)-N-phthalimido]diphenyl methane,4,4'-bis[(4-carboxy)-N-phthalimido]diphenyl sulfone,4,4'-bis[(4-carboxy)-N-phthalimido]diphenyl sulfide,4,4'-bis[(4-carboxy)-N-phthalimido]diphenyl ketone,3,4'-bis[(4-carboxy)-N-phthalimido]diphenyl ether,3,4'-bis[(4-carboxy)-N-phthalimido]diphenyl sulfide,3,4'-bis[(4-carboxy)-N-phthalimido]diphenyl sulfone,3,4'-bis[(4-carboxy)-N-phthalimido]diphenyl ketone and3,4'-bis[(4-carboxy)-N-phthalimido]diphenylmethane.

(Compounds of the formulae I and II are obtainable for example by themethod of J. Polym. Sci. (A-1) 7 (1969), 32-332.)

(b) from 0 to 30 mole %, in particular from 0 to 20 mole %, of repeatunits of the formulae III and/or IV ##STR12## suitable startingcompounds being for example terephthalic acid and isophthalic acid,

(c) a molar amount corresponding to the total amount of components (a)and (b) of one or more of the repeat units of the formulae V, VI, VII,VIII and IX ##STR13## suitable starting materials being for examplep-aminophenol for units of the formulae V, m-aminophenol for units ofthe formula VI, hydroquinone for units of the formula VII, resorcinolfor units of the formula VIII and 4,4'-dihydroxybiphenyl for units ofthe formula IX,

(d) if desired from 5 to 25 mole %, in particular from 5 to 20 mole %,of one or more of the repeat units of the formulae X, XI and XII##STR14## suitable starting materials being for example m-hydroxybenzoicacid for units of the formula X, p-aminobenzoic acid for units of theformula XI and m-aminobenzoic acid for units of the formula XII,

(e) repeat units, in particular in an amount of not less than 10 mole %,of the formula XIII ##STR15## a suitable starting compound being forexample p-hydroxybenzoic acid. It will be readily understood that themole percentages of components (a), (b), (c), (d) and (e) add up to 100mole % in each case.

Advantageously the polyester amide imides according to the inventioncontain as component (c) from 5 to 20 mole % of repeat units of theformula VI and/or from 2 to 8 mole % of repeat units of the formula Vand/or from 5 to 20 mole % of one or more of the repeat units of theformula VII, VIII or IX.

Particular preference is given to polyester amide imides which containas component (c) from 5 to 20 mole % of repeat units of the formula VI,from 5 to 15 mole % of repeat units of the formula XII and from 5 to 15mole % of repeat units of the formula IX.

Other preferred polyester amide imides contain as component (c) from 5to 20 mole % of repeat units of the formula VI and from 5 to 15 mole %of repeat units of the formula VII.

Preferred wholly aromatic polyester amide imides according to theinvention have a glass transition temperature of ≧140° C., in particular≧150° C. The glass transition temperature is measured by the DSCdifferential scanning colorimetry method as described by K. H. Illers etal. in Makromol. Chemie 127 (1969), 1 ff. The wholly aromaticliquid-crystalline polyester amide imides of the invention form aliquid-crystalline fiber-forming melt at below 320° C. Preference isalso given to liquid-crystalline aromatic polyester amide imides whichhave partial crystallinity at a temperature >200° C. and <300° C.

The liquid-crystalline polyester amide imides according to the inventionare obtained in a manner similar to techniques as described for examplein U.S. Pat. Nos. 4,375,530 and 4,118,372.

In an advantageous embodiment, the polyester amide imides according tothe invention are obtained in a single-stage process by converting thestarting materials as underivatized carboxylic acids, hydroxy compoundsor amino compounds using anhydrides of lower fatty acids, for examplefatty acids of 2 to 4 carbon atoms, in particular acetic anhydride. Thisconversion may also be catalyzed with catalysts of the type describedfor example In EP-A-131,846 (page 9), used in an amount of from 0.001 to1% by weight. In the preferred embodiment, the starting materials areheated together with a fatty acid anhydride, which is advantageouslypresent in a molar excess of 5% or more, based on the hydroxyl and aminogroups present, with stirring in an inert gas atmosphere to atemperature at which reflux occurs. Advantageously the temperature israised in stages, for example to 130° to 200° C. in not more than 5hours, preferably up to 2 hours, and the temperature is then raised to250°-350° C., for example in the course of from 2 to 21/2 hours, duringwhich excess fatty acid anhydrides and fatty acids are distilled off. Tocomplete the reaction it has been found to be advantageous to employreduced pressure, for example from 200 to 0.1 mbar, toward the end.

The wholly aromatic liquid-crystalline polyester amide imides thusobtained can subsequently be further condensed in the solid state, forexample at 150°-250° C. in the solid phase below the melting point,until the desired viscosity is obtained. This postcondensation in solidphase can be carried out not only before but also after thermoplasticprocessing. Advantageously the condensation in solid phase is carriedout in the presence of insert gases, for example nitrogen.

It is a remarkable and unforeseeable feature of this single-stageprocess that the desired polymers are obtained in a relatively shorttime in a trouble-free and complete reaction without catalysts. This isall the more remarkable as the large number of chemically differenthydroxyl and amino groups would have been expected to lead todifferences in reactivity and hence inadequate polymer synthesis.

The polyester amide imides according to the invention can containcustomary additives such as stabilizers, oxidation inhibitors, agentsagainst thermal decomposition and decomposition by ultraviolet light,lubricants, mold release agents, colorants such as dyes and pigments,fibrous and pulverulent fillers and reinforcing agents, plasticizers andnucleating agents in conventional active amounts.

The stabilizers can be added to the polymers at any stage of processingor when complete. Preferably the stabilizers are added early on toprevent the onset of decomposition before the polymers are protected.

Suitable oxidation inhibitors and heat stabilizers are for examplehalides of metals of group I of the periodic table, for example ofsodium, potassium, lithium with copper(I) halides, for example chloride,bromide or iodide, and also sterically hindered phenols, hydroquinones,various substituted representatives of these groups and combinationsthereof, in concentrations up to 1% by weight, based on the polymer.

Suitable UV stabilizers which are employed in amounts of up to 2% byweight, based on the composition, are for example substitutedresorcinols, salicylates, benzotriazoles or benzophenones.

Further additives are for example organic dyes such as nigrosine orpigments such as titanium dioxide, cadmium sulfide, cadmium selenide,phthalocyanines, ultramarine blue or carbon black, which are employedfor example in amounts of up to 5% by weight, based on the polymer.

Further suitable additives are fibrous or pulverulent fillers andreinforcing agents such as carbon fibers, glass fibers, amorphoussilica, asbestos, calcium silicate, aluminum silicate, magnesiumcarbonate, kaolin, feldspar, chalk, quartz powder or mica, for examplein amounts of up to 70% by weight of the polymer.

Other suitable additives are nucleating agents such as talcum, calciumfluoride, sodium phenylphosphinate, aluminum oxide or finely dividedpolytetrafluoroethylene.

Suitable additives are also plasticizers, for example in amounts of upto 20% by weight of the polymer, for example dioctyl phthalate, dibenzylphthalate, butyl benzyl phthalate, hydrocarbon oils,N-n-butylbenzenesulfonamide, and o- and p-tolueneethylsulfonamide.

The wholly aromatic liquid-crystalline polyester amide imides accordingto the invention are suitable for preparing filaments, fibers, films,foams and industrial moldings by injection molding, pressing orextruding. The moldings prepared from the polyester amide imidesaccording to the invention have excellent mechanical properties such asstiffness, strength and resilience. They are extremely resistant tochemicals and of low flammability. They also have a high heat distortionresistance and a smooth, abrasion-resistant surface. The polyester amideimides according to the invention are therefore highly suitable forpreparing articles for electrical engineering, data processing,automotive construction and other industrial sectors. But they can alsobe used as coating materials, for example in the form of a pulverulentdispersion or as a film.

The invention is illustrated by the following examples.

EXAMPLE 1

0.15 mol of terephthalic acid, 0.26 mol of 4-hydroxybenzoic acid, 0.07mol of hydroquinone, 0.07 mol of dihydroxybiphenyl, 0.06 mol of3-aminophenol and 0.05 mol of the compound ##STR16## and 84 ml of aceticanhydride are heated with stirring under nitrogen from 150° C. to 300°C. in the course of 3 h, while excess acetic anhydride and acetic acidis distilled off. The pressure is then reduced to 240 mbar in the courseof 1 h 15 min to give a viscous fiber-forming melt. The polymer melt andthe cold polymer have a pearlescent luster. The polymer has a smooth,hard and abrasion-resistant surface. DSC differential scanningcolorimetry measurements indicate a glass transition temperature of 150°C. and a melting point of 260° C. The intrinsic viscosity is 1.00 dl/g,measured at 60° C. in 0.1% strength (wt./vol.) solution inpentafluorophenol.

EXAMPLE 2

0.10 mol of terephthalic acid, 0.26 ml of 4-hydroxybenzoic acid, 0.07mol of hydroquinone, 0.03 mol of dihydroxybiphenyl, 0.10 mol of3-aminophenol and 0.1 mol of the compound ##STR17## and 84 ml of aceticanhydride are heated with stirring under nitrogen from 150° C. to 300°C. in the course of 2 hr 45 min, while excess acetic anhydride andacetic acid is distilled off. The pressure is then reduced to 80 mbar inthe course of 50 min to give a viscous, pale, fiber-forming melt. Thepolymer melt and the cold polymer have a pearlescent luster. The polymerhas a smooth, hard and abrasion-resistant surface. DSC differentialscanning colorimetry measurements indicate a glass transitiontemperature of 177° C. The intrinsic viscosity is 0.82 dl/g, measured at60° C. in 0.1% strength (wt./vol.) solution in pentafluorophenol.

EXAMPLE 3

0.085 mol of terephthalic acid, 0.22 mol of 4-hydroxybenzoic acid, 0.085mol of hydroquinone, 0.085 mol of 3-aminophenol and 0.085 mol of thecompound ##STR18## and 96 ml of acetic anhydride are heated withstirring under nitrogen from 150° C. to 300° C. in the course of 2 hr 50min, while excess acetic anhydride and acetic acid is distilled off. Thepressure is then reduced to 40 mbar in the course of 20 min to give aviscous fiber-forming melt. The polymer melt and the cold polymer have apearlescent luster. The polymer has a smooth, hard andabrasion-resistant surface. DSC differential scanning colorimetrymeasurements indicate a glass transition temperature of 181° C. Theintrinsic viscosity is 0.37 dl/g, measured at 60° C. in a 0.5% strength(wt./vol.) solution in p-chlorophenol.

We claim:
 1. A wholly aromatic mesomorphic polyester amide imide whichforms a liquid-crystalline fiber-forming melt below 320° C., composedof(a) from 5 to 35 mole % of repeat units of the formula I or II ormixtures thereof ##STR19## where the Xs in the formulae I and II areidentical or different and each is --O--, --S--, --SO₂ --, --CO--, --CH₂-- or --C(CH₃)₂ and n is 0 or 1, (b) from 0 to 30 mole % of repeat unitsof the .[.formulae.]. .Iadd.formula .Iaddend.III or IV or mixturesthereof ##STR20## (c) a molar amount corresponding to the total amountof components .[.a.]. .Iadd.(a) .Iaddend.and .[.b.]. .Iadd.(b).Iaddend.of repeat units of the .[.formulae.]. .Iadd.formula .Iaddend.V,VI, VII.Iadd., VIII .Iaddend.or IX or mixtures thereof, with thestipulation that a molar quantity greater than zero of V, VI or mixturesthereof must be present at all times ##STR21## .[.from 5 to 25 mole % ofrepeat units of the formula X, XI or XII or mixtures thereof:.].##STR22## .Iadd.and .Iaddend. (e) repeat units of the formula XIII##STR23## the mole percentages of components (a), (b) (c).[., (d).]. and(e) adding up to 100 mole % in each case.
 2. A wholly aromaticmesomorphic polyester amide imide as claimed in claim .[.1.]. .Iadd.11,.Iaddend.composed of(a) from 7 to 25 mole % of repeat units of the.[.formulae.]. .Iadd.formula .Iaddend.I or II .Iadd.or mixtures thereof.Iaddend. (b) from 0 to 20 mole % of repeat units of the .[.formulae.]..Iadd.formula .Iaddend.III or IV .Iadd.or mixtures thereof .Iaddend.(c)a molar amount corresponding to the total amount of components (a) and(b) of repeat units of the .[.formulae.]. .Iadd.formula .Iaddend.V, VI,VII, VIII or IX or mixtures thereof with the proviso that a molarquantity greater than zero of V, VI or mixtures thereof must be presentat all times (d) from 5 to 20 mole % of repeat units of the.[.formulae.]. .Iadd.formula .Iaddend.X, XI or XII or mixtures thereofand (e) repeat units of the formula XIII, the mole percentages ofcomponents (a), (b), (c), (d) and (e) adding up to 100 mole % in eachcase.
 3. A wholly aromatic mesomorphic polyester amide imide as claimedin claim 1, which contains as component (c) from 5 to 20 mole % ofrepeat units of the formula VI or mixtures of 5 to 20 mole % of therepeat units of the formula VI and 2 to 8 mole % of repeat units of theformula V and from 5 to 20 mole % of one or more of the repeat units ofthe .[.formulae.]. .Iadd.formula .Iaddend.VII, VIII or IX.
 4. A whollyaromatic mesomorphic polyester amide imide as claimed in claim 1, whichcontains as component (c) from 5 to 20 mole % of repeat units of theformula VI and from 5 to 15 mole % of repeat units of the formula VIIand also from 5 to 15 mole % of repeat units of the formula IX.
 5. Awholly aromatic mesomorphic polyester amide imide as claimed in claim 1,which contains as component (c) from 5 to 20 mole % of repeat units ofthe formula VI and from 5 to 15 mole % of repeat units of the formulaVII.
 6. A wholly aromatic mesomorphic polyester amide imide as claimedin claim 1, which contains not less than 10 mole % of repeat units ofthe formula XIII.
 7. A wholly aromatic mesomorphic polyester amide imideas claimed in claim 1, which has a glass transition temperature Tg>140°C.
 8. A fiber from a polyester amide imide as claimed in claim
 1. 9. Afilm from a polyester amide imide as claimed in claim
 1. 10. A moldingfrom a polyester amide imide as claimed in claim
 1. .Iadd.11. A whollyaromatic mesomorphic polyester amide imide which forms aliquid-crystalline fiber-forming melt-below 320° C., composed of(a) from5 to 35 mole % of repeat units of the formula I or II or mixturesthereof ##STR24##.Iaddend. where the Xs in the formulae I and II areidentical or different and each is --O--, --S--, --SO₂ --, --CO--, --CH₂-- or --C(CH₃)₂ -- and n is 0 or 1, (b) from 0 to 30 mole % of repeatunits of the formula III or VI or mixtures thereof ##STR25## (c) a molaramount corresponding to the total amount of components (a) and (b) ofrepeat units of the formula V, VI, VII, VIII or IX or mixtures thereof,with the stipulation that a molar quantity greater than zero of V, VI ormixtures thereof must be present at all times ##STR26## (d) from 5 to 25mole % of repeat units of the formula X, XI or XII or mixtures thereof:##STR27## and (e) repeat units of the formula XIII ##STR28## the molepercentages of components (a), (b), (c), (d) and (e) adding up to 100mole % in each case. .Iadd.12. A wholly aromatic mesomorphic polyesteramide imide as claimed in claim 11, which contains as component (c) from5 to 20 mole % of repeat units of the formula VI or mixtures of 5 to 20mole % of the repeat units of the formula VI and 2 to 8 mole % of repeatunits of the formula V and from 5 to 20 mole % of one or more of therepeat units of the formula VII, VIII or IX. .Iaddend. .Iadd.13. Awholly aromatic mesomorphic polyester amide imide as claimed in claim11, which contains as component (c) from 5 to 20 mole % of repeat unitsof the formula VI and from 5 to 15 mole % of repeat units of the formulaVII and also from 5 to 15 mole % of repeat units of the formula IX..Iaddend. .Iadd.14. A wholly aromatic mesomorphic polyester amide imideas claimed in claim 11, which contains as component (c) from 5 to 20mole % of repeat units of the formula VI and from 5 to 15 mole % ofrepeat units of the formula VII. .Iaddend. .Iadd.15. A wholly aromaticmesomorphic polyester amide imide as claimed in claim 11, which containsnot less than 10 mole % of repeat units of the formula XIII. .Iaddend..Iadd.16. A wholly aromatic mesomorphic polyester amide imide as claimedin claim 11, which has a glass transition temperature Tg>140° C..Iaddend. .Iadd.17. A fiber from a polyester amide imide as claimed inclaim
 11. .Iaddend. .Iadd.18. A film from a polyester amide imide asclaimed in claim
 11. .Iaddend. .Iadd.19. A molding from a polyesteramide imide as claimed in claim
 11. .Iaddend.